Method and apparatus for discovering device in wireless communication network

ABSTRACT

A method and apparatus for discovering a device without an access point (AP) to perform P2P communication in a wireless communication network includes: receiving a probe request frame from another P2P device; determining whether a message requesting at least one of a phone number and user identification information is included in the received probe request frame; and transmitting a probe response frame including at least one of the phone number and the user identification information to the another P2P device when the message is included in the probe request frame.

CLAIM OF PRIORITY

This application claims the benefit under 35 U.S.C. §119(a) of a Koreanpatent application filed on Feb. 24, 2012 in the Korean IntellectualProperty Office and assigned Serial No. 10-2012-0018952, the entiredisclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and an apparatus fordiscovering a device in a wireless communication network, and moreparticularly, to a method for discovering a device without an accesspoint (AP), and an apparatus thereof.

2. Description of the Related Art

Among wireless communication technologies, a wireless fidelity (Wi-Fi)direct network technology is a technology which enables Wi-Fi terminalsto be connected to each other in a peer-to-peer (hereinafter referred toas ‘P2P’) fashion without an AP being a medium of an infrastructurenetwork. Most of the existing Wi-Fi technologies are aimed at onlyconnecting to the Internet through a Wireless Local Area Network (WLAN)AP whereby consideration of direct communication between terminals isnot addressed. Direct communication between terminals may be achievedthrough Bluetooth technology. However, the performance quality intransmission distance and transmission speed of Bluetooth technologydeteriorates as compared with the Wi-Fi Direct technology.

An existing Wi-Fi technology supports a mode in which directcommunication between terminals is possible, which is called an Ad-hocmode. However, since the Ad-hoc mode is disadvantageous in that securityis weak, power consumption is high, and throughput is limited to 11Mbps, it is rarely used.

The Wi-Fi direct technology supports Wi-Fi Protected Access® 2 (WPA2) tosupplement weakness of security. Further, the Wi-Fi Direct technologysupports simple connections between terminals using a Wi-Fi SimpleConfiguration (hereinafter referred to ‘WSC’). Moreover, the Wi-Fidirect technology provides an improved power consumption algorithm bysupporting IEEE 802.11n to significantly improve throughput as comparedwith the Ad-hoc mode.

The Wi-Fi direct technology is a protocol manufactured based on IEEE802.11, and is compatible with a legacy client. The Wi-Fi directtechnology may be upgraded in a terminal without changing hardware.

Although the Wi-Fi direct technology has considerable advantages asillustrated above as compared with Bluetooth and Ad-hoc technologies,there is a need for a technology enabling a user to easily recognize afound terminal.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above problems andprovides additional advantages, by providing g a method for discoveringa device capable of improving a user experience (UX) by enabling a userto easily recognize a found terminal, and an apparatus thereof.

In accordance with an aspect of the present invention, a method fordiscovering a peer to peer (P2P) device capable of performing P2Pcommunication in a wireless communication network includes: receiving,by a first P2P device a probe request frame from a second P2P device;determining, by the first P2P device, whether a message requesting atleast one of a phone number and user identification information isincluded in the received probe request frame; and transmitting, by thefirst P2P device, a probe response frame including at least one of thephone number and the user identification information to the second P2Pdevice when the message is included in the received probe request frame.

In accordance with another aspect of the present invention, a method fordiscovering a peer to peer (P2P) device capable of performing P2Pcommunication in a wireless communication network includes:transmitting, by a first P2P device, a probe request frame including amessage requesting a phone number to a second P2P device; receiving, bythe first P2P device, a probe response frame including the phone numberfrom the second P2P device having received the message; displaying, bythe first P2P device, a contact point information associated with thereceived phone number from a phone book; and establishing, by the firstP2P device, a connection with the second P2P device having transmittedthe probe response frame including the phone number when the displayedcontact point information is selected.

In accordance with another aspect of the present invention, a anapparatus for discovering a peer to peer (P2P) device capable ofperforming P2P communication in a wireless communication networkincludes: a Wi-Fi module for performing a function of an access point ora state in the P2P communication and for transmitting, by a first P2Pdevice, a probe request frame to a second P2P device; and a controllercontrolling the Wi-Fi module to transmit, by the second P2P device, aprobe response frame including at least one of the phone number and theuser identification information to the first P2P device when a messagerequesting at least one of a phone number and user identificationinformation is included in the received probe request frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and advantages of the present invention will be moreapparent from the following detailed description in conjunction with theaccompanying drawings, in which:

FIG. 1 is a diagram illustrating a network configuration of a P2P groupaccording to an exemplary embodiment of the present invention;

FIG. 2 is a flowchart illustrating a P2P connection method according toan exemplary embodiment of the present invention;

FIG. 3 is a flowchart illustrating a P2P connection method according toanother embodiment of the present invention;

FIG. 4 is a flowchart illustrating a device discovery process accordingto an exemplary embodiment of the present invention;

FIG. 5 is a flowchart illustrating a provision discovery processaccording to an exemplary embodiment of the present invention;

FIG. 6 is a flowchart illustrating a negotiation process according to anexemplary embodiment of the present invention;

FIG. 7 is a flowchart illustrating a negotiation process according toanother embodiment of the present invention;

FIG. 8 is a flowchart illustrating a method for transmittingidentification information in a wireless communication network accordingto an exemplary embodiment of the present invention;

FIGS. 9, 10, 11 and 12 are diagrams illustrating examples of a proberesponse frame, respectively;

FIG. 13 is a flowchart illustrating a method for using identificationinformation in a wireless communication network according to anexemplary embodiment of the present invention;

FIG. 14 is a diagram illustrating identification information of adiscovered P2P device;

FIG. 15 is a flowchart illustrating a method for transmittingidentification information in a wireless communication network accordingto another embodiment of the present invention; and

FIG. 16 is a block diagram illustrating a configuration of a portableterminal according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

A method and an apparatus for discovering a device according toexemplary embodiments of the present invention are described withreference to the accompanying drawings in detail. The same referencenumbers are used throughout the drawings to refer to the same or likeparts. For the purposes of clarity and simplicity, detailed descriptionsof well-known functions and structures incorporated herein may beomitted to avoid obscuring the subject matter of the present invention.

As used herein, the term “peer to peer (P2P) device” refers to aterminal including a Wi-Fi direct technology acting as a GO and a GC ina Wi-Fi direct network. As used herein, the term “P2P group” refers toone terminal set configured by one GO and one or more GCs in the Wi-Fidirect network. The GC is connected to the GO. The GO communicates witha GC, and performs an AP function relaying communication betweenparticularly GCS.

FIG. 1 is a diagram illustrating a network configuration of a P2P groupaccording to an exemplary embodiment of the present invention. Referringto FIG. 1, the GO may connect with a plurality of GCS or may connectwith one GC. The number of admissible clients may be determinedaccording to a performance of the GO. Such a performance may be ahardware performance and a software performance, which may be a chargingrate of a battery as an example. When a battery of the GO is chargedgreater than 80%, the GO may be connected with four GCs as shown. If thecharging rate of the battery is less than 50%, the GO may be connectedwith one GC. The number of the GCs connected with the GO may be alsodetermined by the user in environmental setting of the terminal. The P2Pdevice is a terminal including the Wi-Fi direct technology and mayinclude, for example, a portable terminal (e.g., tablet PC, notebookPC), a printer, a projector, and a digital TV.

FIG. 2 is a flowchart illustrating a P2P connection method according toan exemplary embodiment of the present invention. Referring to FIG. 2, aP2P device searches a neighboring P2P device, and performs a discoveryprocess connecting with the searched P2P device at step 210. A purposeof the discovery is to search P2P devices such that devices may connectwith each other as soon as possible. The discovery operation includes adevice discovery and a provision discovery. The device discovery isconfigured by two steps, namely, a scan step and a find step.

A probe request frame and a probe response frame are used in the devicediscovery according to the embodiment of the present invention toexchange information between the devices. When the P2P device itself isa GO or in a listen state, the P2P device may respond to a probe requestframe received from another P2P device. Further, if the P2P deviceitself is a GO, it may transmit a beacon frame. If the P2P device is notincluded in a group, it may be in a listen state. That is, the P2Pdevice in the listen state responds to a received probe request frame.

In operation, the P2P device in the listen state selects a listenchannel from a social channel list. For example, according to a Wi-FiP2P Technical Specification suggested by the Wi-Fi Alliance TechnicalCommittee, channels 1, 6, and 11 may be used as a social channel in 2.4GHz band. For example, when channel 1 is selected, the P2P device mayreceive a probe request frame through the channel 1, but may not receivethe probe request frame through other channels. When the devicediscovery starts, the listen channel may be selected and remain untilthe discovery is terminated. If a preset time elapses, the listenchannel may be changed to another channel. A 2.4 GHz band is used andthere are a total of 14 channels in the IEEE 802.11. An interval betweenchannels is 5 MHz, each having a 22 MHz band. The channels are notindependent from each other but overlap with each other. However, threechannels 1, 6, and 11 among the 14 channels do not interfere with eachother.

The scan step in the device discovery is a step of searching for a P2Pdevice or a P2P group. Further, the scan step is a step of searching themost suitable channel to set the P2P group. That is, in the scan step,the P2P device scans all supported channels to collect information froma neighboring device or network. In the scan step, the P2P device maynot respond to a probe request frame.

The find step in the device discovery is a step in which P2P devicesexisting in the same channel transceive a message to find each other.The P2P device waits for reception of the probe request frame in thelisten state. When the probe request frame is received, the P2P devicetransmits a probe response frame to a P2P device of the other party. TheP2P device may change the listen state to a search state. In a searchstate, the P2P device transmits the probe request frame and the P2Pdevice of the other party transmits the probe response frame in responseto the probe request frame. The probe response frame includes a devicename, device attribute information, and vendor information. The P2Pdevice may display the information allowing the user to confirm theinformation.

The P2P devices searched for each other through the device discovery maybe connected to each other. To this end, the P2P device according to theembodiment of the present invention performs a provision discovery witha P2P device of the other party awaiting a connection. When the P2Pdevice attempts a connection with another P2P device in a PersonalIdentification Number (PIN) or a Push Button Configuration (PBC) mode ofWSC, the provision discovery informs a user of the connection attempt.The P2P device receives a provision discovery request frame during theprovision discovery, and informs the user of message contents through apop-up. The pop-up includes information of the P2P device havingrequested the provision discovery such as a device name. The requesteduse of the P2P device determines a presence of admittance and a WSC ofthe connection. To inform the P2P device of the other party of thepresence of admittance of the connection, the P2P device transmits aprovision discovery response frame to the P2P device of the other party.

When the provision discovery is completed, the P2P device negotiates afunction with the P2P device of the other party in step 220. In thisprocedure, a P2P device determined as the GO performs the function ofthe AP, and a P2P device determined as a GC performs the function of astation.

After negotiation of the function is completed, the P2P device exchangesinformation necessary for P2P communication, for example, a network key,an encryption type, a Service Set Identification (SSID), anAuthentication type with the P2P device of the other party to completeP2P connection in step 230.

When the P2P connection is completed, the GO drives a Dynamic HostConfiguration Protocol (DHCP) server to dynamically allocate an IPaddress to a GO in step 240. Here, as is generally known in the art, aDHCP is a protocol which enables a network manager (namely, GO) tomanage and allocate an IP address of a P2P group to the GC. Since aWi-Fi direct technology is a communication technology based on an IPaddress, the GC needs to receive allocation of an IP address. The IPaddress may be allocated during a discovery or negotiation procedure.Accordingly, the speed of the entire P2P connection may be improved.

FIG. 3 is a flowchart illustrating a P2P connection method according toanother embodiment of the present invention. Referring to FIG. 3, a P2Pdevice performs a device discovery for discovering a neighboring P2Pdevice in step 310. Then, the P2P device performs a provisionaldiscovery for connecting with a discovered P2P device in step 310.Particularly, a provision discovery request frame and a provisiondiscovery response frame may include an IP address to be allocated to aGC. Here, the IP address may be a private IP address usable in a localarea, namely, in a corresponding P2P group. The P2P device stores aprivate IP address list. For instance, the private IP address may be“165.213.30.2˜254”. The P2P device may select an optional private IPaddress from the private IP address list, and transmits a provisiondiscovery request message including the selected private IP address toanother P2P device. Further, The P2P device may transmit a messagediscovery response frame including a private IP address to another P2Pdevice. Thereafter, during a negotiation procedure, a P2P devicedetermined as a GC allocates a received private IP address as its IPaddress.

When the provision discovery is completed, the P2P device negotiates afunction with the P2P device of the other party in step 320. In thisprocess, a P2P device determined as the GO performs the function of theAP, and a P2P device determined as a GC perform the function of astation. P2P devices in the P2P group transceive a message to determinea GO. In this case, such a message may include an IP address,particularly, a private IP address. That is, the P2P device selects anoptional private IP address from a private IP address list, andtransmits a message including the selected private IP address to anotherP2P device. A P2P device determined as a GC as the negotiation resultallocates a received private IP address as its IP address.

After negotiation of the function is completed, the P2P device exchangesinformation necessary for P2P communication, for example, a network key,an encryption type, a Service Set Identification (SSID), anAuthentication type with the P2P device of the other party to completeP2P connection in step 330.

FIG. 4 is a flowchart illustrating a discovery process according to anexemplary embodiment of the present invention.

As shown, a user of the first P2P device 410 commands the first P2Pdevice 410 to perform P2P connection in step 411. That is, the useroperates an input unit included in the first P2P device 410, forexample, a touch screen for the P2P connection. Then, the touch screentransfers an input touch event to a controller of a device. Thecontroller detects the P2P connection request, namely, a command ofdevice discovery from the input touch event. Then, the first P2P device410 firstly performs a scan in response to the command of the devicediscovery in step 412. For example, the first P2P device 410 scanschannels 1, 6, and 11 of IEEE 802.11 in sequence to collect informationfrom a neighboring P2P device. After completing the scan operation, thefirst P2P device 410 performs a find step. Meanwhile, a user of thesecond P2P device 420 commands the second P2P device 420 to perform thediscovery in step 421. Accordingly, the second P2P device 420 initiallyperforms a scan in response to a command of the user in step 422. Aftercompleting the scan, the second P2P device 420 performs a find step.

The first P2P device 410 enters a listen state in step 413. The firstP2P device 410 selects channel 1 as the listen channel. If a preset timeelapses, the first P2P device 420 enters a search state in step 414. Thefirst P2P device 410 firstly selects channel 1 to transmit a proberequest frame in the search state. When there is no response, the firstP2P device 410 selects channel 6 to transmit the probe request frame. Inthis case, the second P2P device 420 is in a listen state with respectto channel 6. The second P2P device 420 receives a probe request framethrough channel 6, and transmits a probe response frame through thechannel 6 in response thereto. The first P2P device 410 receives a proberesponse frame from the second P2P device 410 through the channel 6. Inresponse, the first P2P device 410 displays information of the proberesponse frame, for example, a device name, device attributeinformation, vendor information such that the user may confirm theforegoing information. The user may determine the presence of admittanceof connection based on the information in step 415.

FIG. 5 is a flowchart illustrating a provision discovery processaccording to an exemplary embodiment of the present invention. Referringto FIG. 5, a user of the first P2P device 510 commands the first P2Pdevice 510 to admit connection. For example, the user operates an inputunit included in the first P2P device 510, for example, a touch screenfor P2P connections. Then, the touch screen transfers an input touchevent to a controller which is a command for the provision discoveryfrom the input touch event.

The first P2P device 510 initially transmits a provision discoveryrequest frame to the second P2P device 520 in step 501. Here, theprovision discovery request frame includes an IP address. The IP addressin the provision discovery request frame may be a private IP address.Particularly, the private IP address included in the provision discoveryrequest frame may be one of “165.213.30.2˜254”.

The second P2P device 520 transmits a provision discovery response frameto the first P2P device 510 in response to reception of the provisiondiscovery request frame in step 502. In this case, according to thepresent invention, the provision discovery response frame may include anIP address, namely, a private IP address.

FIG. 6 is a flowchart illustrating a negotiation procedure according toan exemplary embodiment of the present invention. Referring to FIG. 6,the first P2P device 610 and the second P2P device 620 are in a state ofperform discovery to find each other. The first P2P device 610 transmitsa GO Negotiation Request frame to the second P2P device 620 in step 610.According to the present invention, the GO negotiation request frameincludes a P2P Information Element (IE), WSC information (IE), an IPaddress.

The IP address of the GO negotiation request frame may be IP address.The IP address of the GO negotiation request frame may be one of“165.213.30.2˜254”.

That is, the first P2P device 610 may optionally select one private IPaddress from a private IP address list, and transmits the GO negotiationrequest frame, including the selected private IP address. However, forexample, “165.213.30.2˜10” is a share to be allocated to a third P2Pdevice, and may be excluded in the selection. Here, the third P2P deviceis a P2P device requesting entry to a P2P group as a P2P client afternegotiation is completed. That is, a P2P device determined as the GO mayallocate one of the “165.213.30.2˜10” to the third P2P device.

The P2P information of the GO negotiation frame may include deviceinformation, a Configuration Timeout, a Listen Channel, a listen channellist, and a Group Owner Intent (hereinafter referred to as ‘GOI’). Here,the GOI is a numeric value indicating intention of a P2P device, namely,a first P2P device 610 having transmitted a corresponding messagebecoming a GO. That is, when the GOI value is great, there is a highpossibility in which a corresponding P2P device is determined as a GO.The range of the GOI may previously be set. For example, 0˜15 may be therange of the GOI. A P2P device selects a value from the GOI range basedon its performance (e.g, a charging rate of a battery) in a GOnegotiation request frame, and transmits the GO negotiation requestframe including the selected value. For example, when the P2P devicereceives its power supply from a notebook PC and an external commercialpower supply, it may select 15 as the GOI.

The second P2P device 620 receives a GO negotiation request frame from afirst P2P device 610, and transmits a GO negotiation response frame inresponse thereto in step 602. According to the present invention, the GOnegotiation response frame includes a P2P Information Element (IE), WSCinformation (IE), and an IP address.

As describe above, an IP address of the GO negotiation response framemay be a private IP address. Particularly, the private IP addressincluded in the GO negotiation response frame may be one of“165.213.30.2˜254”. However, “165.213.30.2˜10” may be omitted because ofthe foregoing reason. That is, “165.213.30.2˜10” is a shared to beallocated to a third P2P device and may be excluded in the selection.Here, the third P2P device is a P2P device requesting an entry to a P2Pgroup as a P2P client after negotiation is completed. That is, a P2Pdevice determined as the GO may allocate one of the “165.213.30.2˜10” tothe third P2P device. P2P information of the GO negotiation responseframe may include device information, a Configuration Timeout, a ListenChannel, a listen channel list, and a GOI.

As described above, the first P2P device 610 and the second P2P device620 exchange the GOI to determine the GO. For example, when the GOIselected by the first P2P device 610 is 10 and the GOI selected by thefirst P2P device 610 is 5, the first P2P device 610 is determined as theGO and the second P2P device 620 is determined as a GC. Accordingly, thefirst P2P device 610 performs a function of an AP in a corresponding P2Pgroup, and the second P2P device 620 performs a function of a station inthe corresponding P2P group. Further, because the first P2P device 610is determined as the GO, the second P2P device 620 allocates an IPaddress received from the first P2P device 610 as its IP address.

The first P2P device 610 transmits a GO Negotiation Confirmation Framethe second P2P device 620 to notify that it is determined as its GO instep 603.

FIG. 7 is a flowchart illustrating a negotiation procedure according toanother embodiment of the present invention. Referring to FIG. 7, thefirst P2P device 710 and the second P2P device 720 are in a state ofperform discovery to find each other. The first P2P device 710 transmitsa GO Negotiation Request frame to the second P2P device 720 in step 701.According to the present invention, the GO negotiation request frameincludes a P2P Information Element (hereinafter referred to as ‘IE’),and WSC IE. The P2P information of the GO negotiation frame may includedevice information, a Configuration Timeout, a Listen Channel, a listenchannel list, and a GOI. Here, the GOI is a numeric value indicating theintention of a P2P device, namely, a first P2P device 710 havingtransmitted a corresponding message becoming a GO. The GOI was describedabove with reference to steps 701 to 703. That is, the first P2P device710 transmits a first GOI to the second P2P device 720 in step 701. Thesecond P2P device 720 transmits a second GOI to the first P2P device 710in step 702. For example, when the first GOI is greater than the secondGOI, the first P2P device 710 may be determined as a GO.

The second P2P device 720 receives a GO negotiation request frame from afirst P2P device 710, and transmits a GO negotiation response frame inresponse thereto in step 702. According to the present invention, the GOnegotiation response frame includes a P2P IE and a WSC IE.

As described earlier, the first P2P device 710 and the second P2P device720 exchange the GOI to determine the GO. For example, the GOI selectedby the first P2P device 710 is greater than that selected by the secondP2P device 720, so that the first P2P device 710 may be determined as aGO. Accordingly, the first P2P device 710 performs a function of an APin a corresponding P2P group, and the second P2P device 720 performs afunction of a station in the corresponding P2P group.

The first P2P device 710 transmits a GO Negotiation Confirmation Frameto the second P2P device 720 to notify that it is determined as its GOin step 703. In particular, according to the present invention, the GONegotiation Confirmation Frame may include an IP address. Here, asdescribed above, the IP address may be a private IP address. The secondP2P device 720 allocates an IP address received from the first P2Pdevice 710 determined as the GO as its IP address.

FIG. 8 is a flowchart illustrating a method for transmittingidentification information in a wireless communication network accordingto an exemplary embodiment of the present invention. Referring to FIG.8, a P2P device receives a probe request frame from another P2P devicein step 801. The P2P device determines whether a message requesting “aphone number and user ID information” is included in the received proberequest frame in step 802.

When the message requesting “phone number and user ID information” isincluded in the received probe request frame, the P2P device transmits aprobe response frame including a P2P device address, a device name, aphone number, and user ID information in step 803. Here, the user IDinformation may include an image. Such an image may be set by a user inenvironmental setting for P2P connection. The P2P device displays a homescreen, which may include an icon corresponding to environmentalsetting. A user may select an icon corresponding to the environmentalsetting. Then, the P2P device detects the selection of the user for anicon corresponding to the environmental setting from the home screen.Further, the P2P device displays an environmental setting screen. In adisplayed state of the environmental setting screen, the user mayoperate an input unit (e.g., touch screen) of the P2P device to set aprofile of the user to be used for P2P connection. Particularly, theuser may select a profile image to be used for P2P connection from aphotograph folder. In addition to the image, the user may include aname, an address, and an e-mail in the profile.

When the message requesting “phone number and user ID information” isnot included in the received probe request frame, the P2P devicetransmits a probe response frame including a P2P device address and adevice name in step 804. That is, the probe request frame at step 804may not include a phone number and user ID information. When the phonenumber and the user ID information are included in all probe responseframes, the size of the frame may be increased and the transmission ofthe frame may be inefficient. Only when the phone number and the user IDinformation are requested, a probe response frame including the phonenumber and the user ID information may be transmitted.

FIGS. 9 to 12 are diagrams illustrating examples of a probe responseframe, respectively. Referring to FIG. 9, when the message requestingthe phone number and the user ID information are not included in theprobe request frame, the P2P device may transmit a probe response frameincluding a device name 910. That is, the probe response frame may notinclude a phone number and user ID information.

Referring to FIG. 10, a P2P device may receive a probe request frameincluding a message 1010 requesting a phone number and user IDinformation as illustrated in FIG. 10( a). In response, the P2P devicemay transmit a probe response frame including a phone number and animage (e.g., thumbnail) as illustrated in FIG. 10( b).

Referring to FIG. 11, the P2P device may transmit a probe response frameonly including a phone number 1110 except for the user ID information.For example, when the other party requests only the phone number, theP2P device transmits only the phone number. Further, when the size of auser profile image exceeds a preset size of a frame, the P2P device maytransmit only the phone number. According to a Wi-Fi directspecification, the size of the probe response frame may be restrictedwithin 1500 bytes. Although it is assumed that only an image is includedin the probe response frame, when a corresponding image exceeds 1500bytes, it may not be transmitted. Accordingly, when the size of theprofile image is too big, the P2P device may transmit only a phonenumber. The P2P device may resize a profile image smaller and transmitthe resized profile image. Further, it is apparent that only a payloadexcept for a header in the small resized profile image may betransmitted. Further, a phone number may be encrypted and the encryptedphone number may be transmitted for privacy protection. The P2P devicehaving received the encrypted phone number may decode and display theencrypted phone number.

Referring to FIG. 12, the P2P device may transmit a probe response frameincluding only an image 1210 except for a phone number. In particular,the P2P device may transmit only a payload except for a header in animage to reduce the size of a probe response frame to be transmitted.For example, the user may set an environment such that a phone number isnot transmitted for privacy of the user. That is, when transmissionprohibition of the phone number is set in environmental setting, the P2Pdevice may transmit an image except for the phone number, or moreparticularly, only a payload. As generally known in the art, the imageincludes a header and a payload. Here, the header includes formatinformation, size information, and palette information of acorresponding image. When knowing a header of the received payload, aP2P device having received the payload may combine the known head withthe received payload to restore the image. Further, the P2P may displaythe restored image.

FIG. 13 is a flowchart illustrating a method for using identificationinformation in a wireless communication network according to anexemplary embodiment of the present invention.

Referring to FIG. 13, a P2P device displays a home screen in step 1301.Here, the home screen includes an icon corresponding to a phone book. Auser may operate an input unit included in the P2P device, for example,a touch screen to activate an icon corresponding to the phone book. Inresponse, the P2P device detects selection of the phone book in step1302, and the P2P device displays the phone book in step 1303. Here, thephone book includes a plurality of contact point information. Eachcontact point information may include a phone number, a recipient name,an image, an e-mail address, and a home page address. In the embodiment,the user may perform a P2P connection through the phone book. That is,the P2P device detects the selection of one contact point from the phonebook. Then, the P2P device may detect a request of P2P connection to aP2P device corresponding to a selected contact point in step 1304 fromthe user. When a function other than the P2P connection, for example, acall request is detected at step 1304, the P2P device performs acorresponding function, namely, attempts a call to a terminal of theselected contact point.

When the request of the P2P connection by the user is detected at step1304, the P2P device performs the foregoing device discovery.Particularly, the P2P device transmits a probe request frame including aphone number and user ID information in step 1305. Further, the P2Pdevice receives a probe response frame including a phone number and userID information in step 1306. Thereafter, the P2P device determineswhether the received phone number is included in the phone book in step1307. When the received phone number is included in the phone book,particularly, when the received phone number corresponds to the selectedcontact point, the P2P device directly performs a provision discoveryprocess in step 1308. That is, the P2P device connects with a P2P devicehaving transmitted the phone number in step 1308. When the receivedphone book is not included in the phone book, the P2P device displaysthe received phone number and user ID information in step 1309. The usermay recognize who is the other party through user ID information. TheP2P device may detect a connection request with a P2P device havingtransmitted a phone number in step 1310. When the connection requestwith a P2P device having transmitted a phone number is detected at step1310, the process goes to step 1308. When the connection request with aP2P device having transmitted a phone number is not detected (that is,when the user does not want connection with the P2P device havingtransmitted a phone number), P2P connection is not performed.

FIG. 14 is a diagram illustrating identification information of adiscovered P2P device. Referring to FIG. 14( a), a P2P device mayreceive a probe response frame including a phone number. Further, theP2P device determines whether a received phone number is included in aphone book. When the received phone number is included in the phonebook, the P2P device may display the received phone number 1410 andcontact point information (e.g., recipient name 1420) associated withthe received phone number 1410. As shown in FIG. 14( a), when one of twodiscovered P2P devices is selected by the user, the P2P device connectswith a P2P device selected by the user.

Alternatively, referring to FIG. 14( b), the P2P device may receive aprobe response frame including a phone number and an image. Further, theP2P device determines whether the received phone number is included in aphone book. When the received phone number is included in the phonebook, the P2P device may display contact point information (e.g., arecipient name 1430) and a received image 1440.

FIG. 15 is a flowchart illustrating a method for transmittingidentification information in a wireless communication network accordingto another embodiment of the present invention. Referring to FIG. 15,when the probe request frame is received, a P2P device selects an imageto be transmitted in step 1501. For instance, the P2P device may selecta profile image set by the user as the image to be transmitted. The P2Pdevice determines whether the size of the selected image exceeds apreset first threshold (e.g., 1024 bytes) in step 1502. When the size ofthe selected image is less than or equal to the preset first threshold,the P2P device transmits a probe response frame including the selectedimage in step 1503.

When the size of the selected image exceeds the preset first threshold,the P2P device changes a format of the selected image in step 1504. Forinstance, the P2P device may change the format of the selected imagefrom a Joint Photographic coding Experts Group (JPEG) to a GraphicInterchange Format (GIF) 89 a using 8 bit color.

The P2P device determines whether the size of the image whose format ischanged exceeds a preset second threshold in step 1505. The secondthreshold at step 1505 may be the same as the first threshold at step1502 or it may be different. When the size of the image whose format ischanged is less than or equal to the second threshold, the P2P devicetransmits a probe response frame including the image whose format ischanged. When the size of the image whose format is changed exceeds thesecond threshold, the P2P device shapes the selected image or the imagewhose format is changed in step 1506. The P2P device according to thepresent invention stores image header information. The image headerinformation may include format information, image size information andimage palette information. For example, the format information may beGIF 89 a, the image size information may be 36 pixels, and the imagepalette information may be a gray image. As described above, the P2Pdevice changes a format of a selected image to GIF 89 a, resizes thesize of the selected image to 36 pixels, and a palette of the selectedimage to a gray image. As mentioned above, if all the images are shaped,payloads of images differ from each other but all headers are the sameas each other. The P2P device removes a header from the shaped image,and transmits a probe response frame including only a payload in step1507. When knowing a header of the received payload, a P2P device havingreceived the payload may combine the known head with the receivedpayload to restore the image, and display the restored image.

As described above, the teachings of the present invention is applicableof P2P electronic device in the various forms. In particular, the P2Pdevice of the present invention is applicable to a portable terminal. Itwill be apparent that the portable terminal is applicable to variousinformation and communication devices and multi-media device such as aportable phone, a smart phone, a tablet PC, a net book PC, a notebookPC, a Portable Multimedia Player (PMP), an electronic book (e-book)reader, a Personal Digital Assistant (PDA), a digital broadcastingplayer, a music player (e.g., MP3 player), a portable game terminal, andapplication devices thereof.

FIG. 16 is a block diagram illustrating a configuration of a portableterminal according to an exemplary embodiment of the present invention.As shown, a portable terminal 1600 according to the present inventionmay include a touch screen 1610, a key input unit 1620, a display unit1630, a memory 1640, a radio frequency (RF) communication unit 1650, anda controller 1660.

The touch screen 1610 is mounted in front of the display unit 1630,generates a touch event in response to a user gesture input thereto. Thecontroller 1660 may detect the touch event input from the touch screen1610 to control the foregoing components.

The key input unit 1620 may include a plurality of input keys andfunction keys for receiving input of numerals and character informationand for setting various functions. The key input unit 1620 generates andtransfers a key signal associated with user setting and function controlof the portable terminal 1600 to the controller 1660. The controller1660 controls the foregoing components in response to the key signal.

The display unit 1630 converts image data input from the controller 1660into an analog signal, and displays the analog signal under control ofthe controller 1660. That is, the display unit 1630 may provide variousscreens according to the use of the portable terminal, for example, alock screen, a home screen, an application execution screen, a menuscreen, a keypad screen a message creation screen, and an Internetscreen. The display unit 1630 may be configured by a flat panel displaysuch as a Liquid Crystal Display (LCD), an Organic Light Emitted Diode(OLED), or an Active Matrix Organic Light Emitted Diode (AMOLED).

The memory 1640 may store an operating system (OS), applicationsnecessary for the invention, and various data. The memory 1640 maychiefly include a program area and a data area. The data area of thememory 1640 may store data generated by the portable terminal 1600 ordata downloaded from the outside, namely, images, documents, video,messages, emails, music, and effect sounds. Further, the data area maystore the screen displayed on the display unit 1630. Moreover, the dataarea may temporarily store data which the user copies messages,photographs, web pages, or documents for copy and paste. In addition,the data area may store various setting values (e.g., screen brightness,presence of vibration when a touch occurs, presence of automaticrotation of a screen) for operating the portable terminal. Further, thedata area may include a private IP address list 1641, a phone book 1642,and image header information 1643. The program area of the memory 1640may store an operating system (OS) for booting the portable terminal andthe foregoing components, and various applications. In particular, theprogram area stores programs associated with an operation and control ofa Wi-Fi direct terminal such as device discovery, provision discovery,and negotiation.

The RF communication unit 1650 performs a voice call, an image call ordata communication under control of the controller 1660. The RFcommunication unit 1650 may include an RF transmitter up-converting afrequency of a transmitted signal and amplifying the signal and an RFreceiver low-noise-amplifying a received signal and down-converting thesignal. Further, the RF communication unit 1650 may include mobilecommunication modules (e.g., a 3-Generation mobile communication module,a 3.5-Generation mobile communication module, or a 4-Generation mobilecommunication module, etc.) and a Wi-Fi module.

The Wi-Fi module 1651 supports wireless communication based on an IP ofthe portable terminal 1600. In the present invention, the Wi-Fi module1651 performs a function of an AP or a station under control of thecontroller 1660. In other words, the Wi-Fi module 1651 acts as a GO or aGC under control of the controller 1660.

The Wi-Fi module 1651 performs a device discovery operation, a provisiondiscovery operation, and negotiation. When a probe request frame isreceived, the Wi-Fi module 1651 may transmit a probe response frameincluding at least one of a phone number and user ID information undercontrol of the controller 1660.

The Wi-Fi module 1651 may include an IP address in a Provision DiscoveryRequest Frame, a Provision Discovery Response Frame, a GO NegotiationRequest Frame, a GO Negotiation Response Frame, or a GO NegotiationConfiguration Frame, and transmit the corresponding frame under controlof the controller 1660. Further, the Wi-Fi module 1651 may receive theIP address included in the Provision Discovery Request Frame, theProvision Discovery Response Frame, the GO Negotiation Request Frame,the GO Negotiation Response Frame, or the GO Negotiation ConfigurationFrame, and transfer the received IP address to the controller 1660.

The controller 1660 controls an overall operation of the portableterminal 1600, signal flow between internal components of the portableterminal 1600, and processes data. Further, the controller 1660 controlspower supply to the internal components in a battery. Moreover, thecontroller 1660 executes various applications stored in the programarea.

The controller 1660 may receive an event from the touch screen 1610 orthe key input unit 1620, and detect command of the discovery from thereceived event. The controller 1660 controls the Wi-Fi module 1651 toperform the device discovery in response to the command of devicediscovery. The controller 1660 controls the Wi-Fi module 1651 to performthe provision discovery in response to the command of the provisiondiscovery.

The controller 1660 may select a private IP address to be transmittedfrom a private IP address list 1641, and control the Wi-Fi module 1651to transmit the selected private IP address. The controller 1660 mayreceive the private IP address from an external device, namely, a P2Pdevice through the Wi-Fi module 1651. When the portable terminal 1600 isdetermined as a GC after a negotiation, the controller 1660 allocatesthe received private IP address as an IP address of the portableterminal 1600, and operates the Wi-Fi module 1651 as a GC. As anegotiation result, when the portable terminal 1600 is determined as aGO, the controller 1660 operates the Wi-Fi module 1651 as a GO.

The controller 1660 may control a display unit 1630 to display a phonebook 1642. Further, the controller 1660 may detect the selection of onecontact point from the phone book 1642. The controller 1660 may detect arequest of P2P connection (e.g., touch on contact point) to a P2P devicecorresponding to a selected contact point. When the request of the P2Pconnection is detected, the controller 1660 may control the Wi-Fi module1651 to perform P2P connection with a P2P device corresponding to aselected contact point.

The controller 1660 may control a Wi-Fi module 1651 to transmit a proberequest frame including a phone number and a user ID information requestmessage. When the probe request frame including the phone number isreceived, the controller 1660 may extract contact point informationassociated with the received phone number from the phone book 1642, andcontrol the display unit 1630 to display the extracted contact pointinformation.

When receiving a probe response frame including an image payload, thecontroller 1660 may restore an image with reference to image headerinformation 1643 to restore an image, and control the display unit 1630to display the restored image. The controller 1660 shapes an image withreference to the image header information 1643, and removes a headerfrom the shaped image. Further, the controller 1660 may include aremainder from which a header is removed, a payload in a probe responseframe, and control the Wi-Fi module 1651 to transmit the probe responseframe.

Meanwhile, the portable terminal 1600 may further include constructionsthat are not mentioned such as a digital broadcasting module (e.g., DMBmodule), a GPS module, and a camera module.

The foregoing method for allocating an IP address of the presentinvention may be implemented in an executable program command form byvarious computer means and be recorded in a computer readable recordingmedium. In this case, the computer readable recording medium may includea program command, a data file, and a data structure individually or acombination thereof. In the meantime, the program command recorded in arecording medium may be specially designed or configured for the presentinvention or be known to a person having ordinary skill in a computersoftware field to be used. The computer readable recording mediumincludes Magnetic Media such as hard disk, floppy disk, or magnetictape, Optical Media such as Compact Disc Read Only Memory (CD-ROM) orDigital Versatile Disc (DVD), Magneto-Optical Media such as flopticaldisk, and a hardware device such as ROM. RAM, flash memory storing andexecuting program commands. Further, the program command includes amachine language code created by a complier and a high-level languagecode executable by a computer using an interpreter. The foregoinghardware device may be configured to be operated as at least onesoftware module to perform an operation of the present invention.

Although a method and apparatus for allocating an IP address accordingto exemplary embodiments of the present invention have been described indetail hereinabove, it should be clearly understood that many variationsand modifications of the basic inventive concepts herein taught whichmay appear to those skilled in the present art will still fall withinthe spirit and scope of the present invention, as defined in theappended claims.

What is claimed is:
 1. A method for discovering a peer to peer (P2P)device capable of performing P2P communication in a wirelesscommunication network, the method comprising: receiving, by a first P2Pdevice a probe request frame from a second P2P device; determining, bythe first P2P device, whether a message requesting user identificationinformation is included in the probe request frame; and selecting animage from stored images and transmitting, by the first P2P device, aprobe response frame including the selected image to the second P2Pdevice when the message is included in the probe request frame.
 2. Themethod of claim 1, further comprising: restoring and displaying theimage based on a stored image header information.
 3. The method of claim1, wherein the transmitting of the probe response frame comprises:determining whether a size of the selected image exceeds a preset firstthreshold; and transmitting the selected image when the size of theselected image is less than or equal to the preset first threshold. 4.The method of claim 3, wherein the transmitting of the probe responseframe comprises: changing a format of the selected image when the sizeof the selected image exceeds the preset first threshold; andtransmitting the image whose format is changed when the size of theimage whose format is changed is less than or equal to a preset secondthreshold.
 5. The method of claim 4, wherein the transmitting of theprobe response frame comprises: shaping the selected image or the imagewhose format is changed based on a stored image header information whenthe size of the image whose format is changed exceeds the preset secondthreshold; and transmitting a payload except for a header from theshaped image.
 6. The method of claim 5, wherein the image headerinformation includes at least one of format information, image sizeinformation, and image palette information.
 7. The method of claim 1,wherein the transmitting of the probe response frame comprises: shapingthe selected image based on a stored image header information; andtransmitting a payload except for a header from the shaped image.
 8. Themethod of claim 1, further comprising: transmitting the probe requestframe including the message while device phone book is displayed.
 9. Themethod of claim 8, further comprising: receiving the probe responseframe including a phone number; and displaying contact point informationfrom the phone book associated with the user identification information.10. The method of claim 8, further comprising: receiving by a second P2Pdevice the probe response frame including the user identificationinformation; and establishing a connection with the second P2P when theuser identification information is associated with a request toestablish a P2P connection.
 11. A device communication method,comprising: receiving, by a first wireless communication device, amessage from a second wireless communication device in a wirelesscommunication network; and selecting an image from stored images andtransmitting, by the first wireless communication device, informationincluding a user identification information further including the imageto the second wireless communication device when a request for theinformation is included in the message.
 12. A method for discovering apeer to peer (P2P) device capable of performing P2P communication in awireless communication network, the method comprising: transmitting, bya first P2P device, a probe request frame including a message requestinga user identification information; receiving, by the first P2P device, aprobe response frame including user identification information whichfurther includes a payload of an image; storing the image anddisplaying, by the first P2P device, a contact point informationincluding the image associated with the user identification informationbased on a stored image header information; and establishing, by thefirst P2P device, a connection with a second P2P device havingtransmitted the probe response frame including the user identificationinformation when the displayed contact point information is selected.13. An apparatus for discovering a peer to peer (P2P) device capable ofperforming P2P communication in a wireless communication network,comprising: a Wi-Fi module for performing a function of an access pointor a state in the P2P communication and for detecting a probe requestframe from another P2P device; and a controller for in response todetecting the probe request frame, selecting an image to be transmittedfrom stored images; detecting whether a size of the selected imageexceeds a preset first threshold; and transmitting by the Wi-fi module aprobe response frame including user identification information furtherincluding the selected image to the another P2P device when a messagerequesting the user identification information is included in thedetected probe request frame, and when the size of the selected image isless than or equal to the preset first threshold.
 14. The apparatus ofclaim 13, wherein when the Wi-Fi module receives the probe responseframe including the image, the controller restores the image based on astored image header information and controls a display unit to displaythe restored image.
 15. The apparatus of claim 13, wherein thecontroller controls the Wi-Fi module to transmit the probe request frameincluding the message requesting the user identification informationwhen a request of P2P connection is detected while the P2P device isdisplaying a phone book.
 16. The apparatus of claim 14, wherein thecontroller changes a format of the selected image when the size of theselected image exceeds the preset first threshold, and controls theWi-Fi module to transmit the image whose format is changed when the sizeof the image whose format is changed is less than or equal to a presetsecond threshold.
 17. The apparatus of claim 16, wherein the controllershapes the selected image or the image whose format is changed based ona stored image header information when the size of the image whoseformat is changed exceeds the preset second threshold, and controls theWi-Fi module to transmit a payload except for a header from the shapedimage.
 18. The apparatus of claim 17, wherein the image headerinformation includes at least one of format information, image sizeinformation, and image palette information.
 19. The apparatus of claim13, wherein the controller shapes the selected image based on storedimage header information, and controls the Wi-Fi module to transmit apayload except for a header from the shaped image.